This is a better thread than not even making it into two pages of comments.
I wonder, for the sake of argument, if one was to take a medium-popular car here (say an Escort) and finish it to that level in terms of paint and some body changes, air-ride or something too, and fit a shiny engine in, but not actually make it driveable (very easy to do a smoothed engine bay then!) - do you think that would make for a show winner here in the same way some of these cars are display pieces rather than a self propelled automobile?
I don't know about England and the big shows, but I don't think I could think of one car over here that is a non-running show build only that couldn't at least make an attempt at an MOT.
I do know a couple of years ago someone I know took an unfinished car to a show and it didn't run, it was on air and had been whatever the monocoque version of channelled is, but that was because he ran out of time and the car was finished off later.
I suppose we don't have very many true customs here any more, not like the 90s when the American & Kit Car Club was rolling 15-strong to every show going, there were some wild rides then. I quite like the idea of an "art-piece" though, purely aesthetic, no requirement for it to drive - you could do all sorts of things then with the wiring and empty space (where a fuel tank should be, etc).